diff options
| -rw-r--r-- | drivers/scsi/sd.c | 78 |
1 files changed, 44 insertions, 34 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 09f49e427f16..9cdfbbe27d0e 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1007,6 +1007,28 @@ sd_read_capacity(Scsi_Disk *sdkp, char *diskname, sdkp->device->sector_size = sector_size; } +static int +sd_do_mode_sense6(Scsi_Device *sdp, Scsi_Request *SRpnt, + int modepage, unsigned char *buffer, int len) { + unsigned char cmd[8]; + + memset((void *) &cmd[0], 0, 8); + cmd[0] = MODE_SENSE; + cmd[1] = (sdp->scsi_level <= SCSI_2) ? ((sdp->lun << 5) & 0xe0) : 0; + cmd[2] = modepage; + cmd[4] = len; + + SRpnt->sr_cmd_len = 0; + SRpnt->sr_sense_buffer[0] = 0; + SRpnt->sr_sense_buffer[2] = 0; + SRpnt->sr_data_direction = SCSI_DATA_READ; + + scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer, + len, SD_TIMEOUT, MAX_RETRIES); + + return SRpnt->sr_result; +} + /* * read write protect setting, if possible - called only in sd_init_onedisk() */ @@ -1014,50 +1036,38 @@ static void sd_read_write_protect_flag(Scsi_Disk *sdkp, char *diskname, Scsi_Request *SRpnt, unsigned char *buffer) { Scsi_Device *sdp = sdkp->device; - unsigned char cmd[8]; - int the_result; + int res; /* - * For removable scsi disks we have to recognise the - * Write Protect Flag. This flag is kept in the Scsi_Disk - * struct and tested at open ! - * Daniel Roche ( dan@lectra.fr ) - * - * Changed to get all pages (0x3f) rather than page 1 to - * get around devices which do not have a page 1. Since - * we're only interested in the header anyway, this should - * be fine. - * -- Matthew Dharm (mdharm-scsi@one-eyed-alien.net) - * - * As it turns out, some devices return an error for - * every MODE_SENSE request except one for page 0. - * So, we should also try that. --aeb + * First attempt: ask for all pages (0x3F), but only 4 bytes. + * We have to start carefully: some devices hang if we ask + * for more than is available. */ + res = sd_do_mode_sense6(sdp, SRpnt, 0x3F, buffer, 4); - memset((void *) &cmd[0], 0, 8); - cmd[0] = MODE_SENSE; - cmd[1] = (sdp->scsi_level <= SCSI_2) ? - ((sdp->lun << 5) & 0xe0) : 0; - cmd[2] = 0x3f; /* Get all pages */ - cmd[4] = 255; /* Ask for 255 bytes, even tho we want just the first 8 */ - SRpnt->sr_cmd_len = 0; - SRpnt->sr_sense_buffer[0] = 0; - SRpnt->sr_sense_buffer[2] = 0; - SRpnt->sr_data_direction = SCSI_DATA_READ; - - scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer, - 255, SD_TIMEOUT, MAX_RETRIES); + /* + * Second attempt: ask for page 0 + * When only page 0 is implemented, a request for page 3F may return + * Sense Key 5: Illegal Request, Sense Code 24: Invalid field in CDB. + */ + if (res) + res = sd_do_mode_sense6(sdp, SRpnt, 0, buffer, 4); - the_result = SRpnt->sr_result; + /* + * Third attempt: ask 255 bytes, as we did earlier. + */ + if (res) + res = sd_do_mode_sense6(sdp, SRpnt, 0x3F, buffer, 255); - if (the_result) { - printk("%s: test WP failed, assume Write Enabled\n", - diskname); - /* alternatively, try page 0 */ + if (res) { + printk(KERN_WARNING + "%s: test WP failed, assume Write Enabled\n", diskname); } else { sdkp->write_prot = ((buffer[2] & 0x80) != 0); printk(KERN_NOTICE "%s: Write Protect is %s\n", diskname, sdkp->write_prot ? "on" : "off"); + printk(KERN_DEBUG "%s: Mode Sense: %02x %02x %02x %02x\n", + diskname, buffer[0], buffer[1], buffer[2], buffer[3]); } } |